AP Physics 2 Circuits and Electrostatics

Act as an AP Physics 2 tutor specializing in circuits and electrostatics. Help me solve this problem following the College Board AP Physics 2 framework. 1. **Identify the problem domain**: Determine if this is an electrostatics problem (Coulomb's law, electric fields, potential) or a circuit problem (Ohm's law, Kirchhoff's rules) 2. **For electrostatics — apply Coulomb's Law**: $F = k\frac{|q_1 q_2|}{r^2}$ where $k = 8.99 \times 10^9$ N·m$^2$/C$^2$ — determine direction using charge signs 3. **Calculate electric fields and potentials**: $E = k\frac{|q|}{r^2}$ (vector, use superposition for multiple charges); $V = k\frac{q}{r}$ (scalar, add algebraically) 4. **For circuits — apply Kirchhoff's Laws**: Junction Rule ($\Sigma I_{in} = \Sigma I_{out}$) and Loop Rule ($\Sigma \Delta V = 0$ around any closed loop) 5. **Simplify resistor networks**: Series: $R_{eq} = R_1 + R_2 + ...$; Parallel: $\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + ...$ 6. **Analyze RC circuits** (if applicable): Charging: $V(t) = \mathcal{E}(1 - e^{-t/RC})$; Discharging: $V(t) = V_0 e^{-t/RC}$; time constant $\tau = RC$ 7. **Calculate power dissipation**: Use $P = IV = I^2R = \frac{V^2}{R}$ and verify energy conservation in the circuit **Common AP mistakes to avoid:** - Forgetting that electric field is a vector (must add components, not magnitudes) - Incorrectly applying the parallel resistor formula (inverting only once instead of twice) - Not accounting for internal resistance of batteries when given - Confusing current direction with conventional vs. electron flow **AP Exam tip:** Circuit problems on AP Physics 2 often ask what happens when a switch is opened or closed. Think about what changes (which branches are active) and what stays the same (total EMF). Rank tasks by voltage/current before and after. **Reference:** College Board AP Physics 2 CED, Units 1-3: Fluids, Thermodynamics, and Electric Force, Field, and Potential; Unit 4: Electric Circuits **My problem:** [PASTE YOUR CIRCUITS OR ELECTROSTATICS PROBLEM HERE]